Stripper for subdivided catalyst particles



Aug. 19,1952 1 L c. HUFF 2,607,662

STRIPPER FOR SUBDIVIDED CATALYST PARTICLES Filed'Jan. 50, 1946 Patented Aug. 19, 1952 STRIPPER'FOR SUBDIVIDED CATALYVST A Y PARTICLES lLyman C. Huil, Evanstom'lll., assignor to Universal Oil Products Company, Chicago, Ill., a corporation of Delaware lApplication January 30, 1946, Serial No. 644,402

, y .1. This invention relates to an improved apparatus for stripping adsorbed and occluded volatile matter from small subdivided particles.

The principal object of 'the invention`is to provide an improved stripping or contact chamcombustible gaseous material Which can be ber, wherein countercurrent flow of small solid mixed with the reaction products Without adparticles andvafluid mediumlis employed, such versely aiecting` their quality or which can be that positive'equ'alized contact is obtained beeasily separated therefrom. tween the two across the .entireehember- The improved apparatus of the present in- FOI instante, in afflllid Catalytic COIIVSTSOII vention utilizes a modified bubble-cap type of unit it S desirable t0 Strip Contaminated Catalyst contacting deck or distributing plate which may particles after their contact-with the reactants be placed at spaced levels Wil-,hln an elongated in the reaction zone and prior to their regeneralStripping chamben Each deck is provided with tion in an OXdZIlg H6 The emOVl 0f a plurality of vapor risers, each having a bubblevolatile hydrocarbonaceous material from the l5 cap or deectirrg platerposltroned a Short dls particles reduces the load'on'th'e regeneration tance above, and a plurality of Open downplpes System as Well aslessenng the possibility 0f 9X which pass catalyst from one level to the next CeSSVe temperatures dllllng regeneration and the lower level. In addition, Vv,equalized streams of resultant damageto the catalyst itselfstripping gas are conducted to and discharged In the operation of theV usual 'iiudized type 20 upwardly Within each of the Vapor risers by of catalyst conversion unit, a dense bed of submeans of a suitable' piping System arranged to divided catalyst particles is maintained Within a distribute stripping gas at each Vapor riser 0pen reacion. Zone in a' State hindered Settling by a' ing and at the level of each distributing plate. commuouestream' of Wtpmfms` or gaseous re" The principal advantage of this improved stripactants which contact the catalyst particles.` A 25 ping apparatus is that an even and equalzed stream. of contannnatedA catalyst, upon Whlh countercurrent flow between catalyst particles deletemousf heavy -hyereeereeneeeeus products and the stripping medium is attained throughare deposlted. is eentmuously *Wlthdrewn from out the entire transverse area of the strippingr the fluid bed lnthereaction Zone to a regeneratcolumn Y D mg Zone Wherem the .Contaminants are remeved In practice, it has been found that considerable te restore the eatalytle actu/ley of the pertleles channeling occurs in conventional strippers of The particles in the regenerating zone are mainthe type Where' the Stripping eas is charged et tained in'a fluidized state of hindered settling nl t t t th 1 d f th by the continuous stream of oxidizing gas which et .y ene er We pom s e e oWer en. .e e affects burningv and removal of the deleterious s .mppmg Zone' In Such Stmppers the neme gas carbonaceous material on the particles. In a e" Wm of .eourse take the path of least reslstanee normal operation of the unit, a light catalyst m paesmg dlreetly upwardly through the de' phase existe abeve the dens e phase bed in both scendmg column of catalyst part1cles, and unless the reaction and regenerating zones. The re- Very posmve centrol means are prevldee ee preaction products are separated from the catalystA Vern; Zeree of. hlgh en d 10W eet'elyst densltles the in this light phase region of the reaction Zone and ee rng el eppmg medlum, Wm' tend te bubble er discharged therefrom to ow through suitable egtedse f Eelpwerdlyn nrrow' hmted plths' fractionation or treating equipment. Flue gases been em le peel eetellf gli s e Veretus ypefs teve and combustion products are separated from the in Zenle yh W1 m .tehpsen (Types et s mpg catalyst in the light phase region of the regeny plage it iss osggev' X1 the. Ort lila?, yrte 10e erating zone and are discharged therefrom to L .1d pd .te to Ve te'sa ys pe lele" the atmosphere, either directly or through suitu1 iup m enel y. e .e eX en et Sme p1 es able heat recovery apparatus. l may .crm at certaln points above the plate and t the rising gas will ow upwardly, through only a ,Contamlneted catalyse parelelee Whleh are few of the holes provided at the zones Where the withdrawn from the reaction zone will, of course, catalyst density is the least be Suspended in hYdmQaTbOn gases 01' Yapf's One of the features'of this invention resides unless Some gaseous medlum' Sruh as a' Stn-ppm? in discharging stripping liuid through outlets gas, dsplaces them- AS PleVlOUSY nOed, 1t 1S which are uniformly spaced across the horizontal very desirable to displace the hydrocarbon gas as area 0f the Stripping column, with a particular a suspension medium, as Well as eilect purging of advantage being obtained bydischarging through 10 Claims. (Cl. 23-288) the catalyst particles of any adsorbed volatile material, in order to aid the operation of the regeneration system. The stripping medium may be steam, ue gas, or other relatively inert nondischarge through each orifice throughout the column. may tend to build up in certain areas of the stripper and increase the pressure above a particular outlet, the variations in densities will never vary more than a few pounds and therefore will not prevent stripping fluid from being discharged equally at all of the outlets. Y

The accompanying drawing and following description thereof will serve to more clearly illustrate the construction features of the apparatus and its advantages for stripping subdivided particles. Y

Figure 1.of the drawing is an elevational View of a reaction chamber with an attached stripping section or `zone such as may be used in a catalytic conversion process. l

Figure 2 is a plan viewY of one of the distributing decks within the stripping zone as indicated Yby line 2-2 in Figure 1.

Figure 3 is a sectional elevation View through a portion of a stripping zone as indicated by line 3-3 in Figure 2. Y

Referring now to Figure l of the drawing, a chamber I is indicated Vsuch as may be employed as a reaction chamber in a fluid.V catalyst conversion process. Heated catalyst and reactants are charged to the reaction zone 2, within the chamberv I, by way of inlet 3. The reactants and catalyst are contacted in a fiuid-like dense phase bed, the top of which is indicated by the broken line V4.'- The depth of this dense phase 3 bed will o f course vary with the quantity of charge, the charge velocity, and average residencertime desired in the reactor. The vapor- Vous reaction products and stripping gases are through outlet 6 and transferred to suitable fractionation and treating equipment, while the separated catalyst isreturned to the dense phase bed by dip pipe 'I, which is attached to the lower end of the separating chamber 5 and causes the catalyst to be discharged below the top level d of the dense phase bed.

Contaminated Vcatalyst is withdrawn through theV elongated stripping chamber or section 8, by descending Ydownwardly therethrough and being discharged through `outlet 9 to a Vsuitable conduit for transferal to a regenerating system. The Vstripping. chamber 8 may be entirely within chamber I, entirely outside, or as in the form shown, partially within the reactor I.. 'A partition plate IG serves to form an elongated stripping section'within the chamber I, and a plurality of distribution plates or decks I I are spaced vertically throughout the stripper. Contaminated catalyst is passed to the stripping section 8 from the open upper end of the stripping zone or through slots I0 which may be provided in the plate I0 between the decks I I.

Stripping steam, flue gas, or other gaseous medium is passed to each of the decks 8 by means of riser line I2 and various horizontal distributting lines I3. Thus, in operation the stripping Thus, even though catalyst densitiesv Y 4 medium is distributed at each deck and will iiow upwardly through the countercurrently descending column of contaminated catalyst so that uniform eficient stripping of volatiles on the catalyst is accomplished.

Figure 2 of the drawing shows a somewhat enlarged plan view of one of the distribution decks II, which extend across the elongated stripping zone 8. A plurality of vertical open passageways or downpipes I are spaced throughout the deck,

each suspended therefrom to terminate at a pointa spaced distance above the next lower distribution plate. Also, spaced across the deck are a plurality of lgas riser openings I5, each preferably'Venturi-like in shape and constructed to extend slightly above the deck plate. Mounted a short distance above each Venturi-like riser I5 there is a downwardly curving plate or bubble cap I6. The riser line I2 has a header I'I at each deck level .and from this header the distributing pipes I3 branch horizontally, in order to enter the stripping chamber and feed a stream of stripping gas at .each of the gas riser openings I5. The now to yeach ofthe headers I1 maybe controlled by means of adjustable valves I8, and in this manner the amount of stripping at each deck may be individually controlled.

A partial elevational view through the stripping zone, as shown in Figure 3 of the drawing, illustrates the construction of the deckA 8 with its riser openings I5, its downpipes I4 and the caps l 6. The distributing lines I3 have stub outlet lines I9 projecting upwardly into each ofthe risers I5, and each of the outlet lines I9 are provided with afixed orifice 20.. The orificesifi provide a pressure drop in the system and means of equalizing the flow of fresh stripping gas te each of the riser openings.

As previously noted, there Vis a resultant countercurrent flow within theV stripper, the catalyst moves downwardly through the pipes I and the stripping medium upwardly through each of the risers I5. Y The additional gas stream from each outlet I9 lserves to insure that stripping gas is passed upwardly-through each of the risers, thus the entire cross-sectional area of Ithe zone is maintained in a uniform-fluid state and no dense pockets of settledcatalyst can accumulate and form on any onedeck. The vapor riser openings I5 are Venturi-like in form. in order to provide, in positive manner, an upward gas flow through each opening. The gas stream from each orice discharging within each riser, will suckerV pull vapors from below each deck such that the total stream will strike the lower side of the cap Iii and be distributed outwardly around its lower edge. The caps I' are vpreferably serrated or notched on their down-turned edges so that theV Ygas stream is broken before contacting -the catalyst.

Also, as previously noted,- it is desired to make sure that the vapor stream passing upwardly through each riser is discharged at a pressure which is greater (by the ratio of 1 to .58) than the downward pressure inthe chamber at any given gas distributing deck. In operation, the catalyst and vapors will be in a rather dense phase just above each deck I I, while a relatively light phase region will exist just below4 each deck where the stripping gas and stripped vapors will have very little catalyst entrained and will be distributed upwardlyA through each of the risers I5. The downpipes I4 are preferably long enough to pass catalyst from above one deck to a level' within the dense phase bed above the next lower deck. y

The improved stripping column of this invention is particularly useful in connection with the fiuidized catalytic cracking of hydrocarbons, however, it may be used in other conversion processes such as hydrogenation, dehydrogenation, desulfurization, etc., and it is not intended to limit the apparatus to catalyst stripping only or to any given operation. The invention can be used as a means of uniformly distributing regenerating gases over the area of a regenerator of a catalytic cracking process, or for distribution of reactant vapors in the reactor of such a process. Also, the stripper need not be limited entirely to the exact details shown, for obviously various structural and construction features may be altered and not change the operation of the apparatus in attaining equalized and eli'icient contacting.

I claim as my invention:

1. An apparatus of the class described comprising a vertically elongated contact chamber having an inlet and an outlet, vertically spaced,`

horizontal distributing plates within said chamber and each provided with a plurality of openings spaced substantially uniformly over its horizontal area, a bailled vapor riser extending upwardly from each of said openings, a fluid inlet pipe projecting upwardly through each of said openings and terminating within the associated riser, a plurality of open-ended pipes extending downwardly from each of said plates and terminating a substantial distance above the vapor risers of the next lower plate in the chamber, and means for supplying fluid to said inlet pipes comprising a conduit extending vertically along the outside of said chamber and spaced from the latter, a plurality of headers, one communicating with said conduit at an elevation slightly below that of each of said plates and horizontal distributing pipes connecting each of said headers with the fluid inlet pipes of one of said plates.

2. The apparatus of claim 1 further characterized in that the baffle of each of said risers comprises a distributing cap spaced above the riser.

3. The apparatus of claim` 1 further characterized in the provision of a flow restriction orifice in each of said inlet pipes.

4. An apparatus of the class described comprising a vertically elongated contact chamber having an inlet and an outlet, vertically spaced, horizontal distributing plates within said chamber and each provided with a plurality of openings spaced substantially uniformly over its horizontal area, a Venturi-like vapor riser extending upwardly from each of said openings, a vapor distributing cap over each of said risers, a uid inlet pipe projecting upwardly through each of said openings and terminating within the associated riser, a plurality of open-ended pipes extending downwardly from each of said plates and terminating a substantial distance above the vapor risers of the next lower plate in the chamber, and means for supplying fluid to said inlet pipes comprising a conduit extending vertically along the outside of said chamber and spaced from the latter, a plurality of headers, one communicating with said conduit at an elevation slightly below that of each of said plates and horizontal distributing pipes connecting each of said headers with the fluid inlet pipes of one of said plates.

5. The apparatus of claim 4 further characterized in the provision of a iiow restriction orice in each of said inlet pipes.

6. A distributing deck comprising a horizontal plate provided with a plurality of openings spaced substantially uniformly over its horizontal area, a baffled Venturi-like vapor riser extending upwardly from each of said openings to an elevation above said plate, a fluid inlet pipe projecting upwardly through each of said openings and terminating within the associated riser, a plurality of open-ended pipes extending downwardly from said plate, and means for supplying fluid to said v inlet pipes.

7. A distributing deck comprising a horizontal plate provided with a plurality of openings spaced substantially uniformly over its horizontal area, a Venturi-like vapor riser extending upwardly from each of said openings to an elevation above said plate, a gas distributing cap over each of said risers and spaced vertically from said plate, a iiuid inlet pipe projecting upwardly through each of said openings and terminating within the associated riser, a plurality of openended pipes extending downwardly from said plate, and means for supplying iiuid to said inlet pipes.

8. A contacting chamber having a vertically extending partition plate therein forming a reaction section and a stripping section, an inlet for charging reactants to said reaction section, means for recovering solids from vapors leaving the upper portion of said reaction section, an outlet from the lower portion of said stripping section, a plurality of spaced horizontal distribution plates extending transversely across said stripping section, openings in said partition plate between said reaction section and said stripping section, a plurality of gas riser openings in each of said horizontal distribution plates, a iiuid inlet pipe extending upwardly into each of said riser openings, a plurality of open-ended pipes extending downwardly from each of said horizontal plates, a cap-like baille spaced above each of said riser openings, and means for supplying fluid to said inlet pipes.

9. The apparatus of claim 8 further characterized in the provision of a xed orifice in each of said inlet pipes.

10. The apparatus of claim 8 further characterized in that said gas riser openings are of Venturi-like construction.

LYMAN C. HUFF.

REFERENCES CITED The following references are of record in the le of this patent: 

6. A DISTRIBUTING DECK COMPRISING A HORIZONTAL PLATE PROVIDED WITH A PLURALITY OF OPENINGS SPACED SUBSTANTIALLY UNIFORMLY OVER ITS HORIZONTAL AREA, A BAFFLED VENTURI-LIKE VAPOR RISER EXTENDING UPWARDLY FROM EACH OF SAID OPENINGS TO AN ELEVATION ABOVE SAID PLATE, A FLUID INLET PIPE PROJECTING UPWARDLY THROUGH EACH OF SAID OPENINGS AND TERMINATING WITHIN THE ASSOCIATED RISER, A PLURALITY OF OPEN-ENDED PIPES EXTENDING DOWNWARDLY FROM SAID PLATE, AND MEANS FOR SUPPLYING FLUID TO SAID INLET PIPES. 